Aircraft fire extinguishing system



. LINDSAY AIRCRAFT FIRE EXTINGUISHING SYSTEM Dec. 14, 1943.

2 she ets-Sheet 1 Filed Sept. 16, 1942 Patented Dec. 14, 1943 OFFICIE AIRCRAFT FIRE EXTINGUISHING SYSTEM Charles 11. Lindsay, Elmira, N. Y., assignor to American-La France-Foamite Corporation, 151- mira, N. Y., a corporation of New York Application September 16, 1942, Serial No. 458,489

2 Claims.

The invention is an improved aircraft fire extinguishing system, employing carbon dioxide or like gas under high pressure as the extinguishing medium, its objects being v primarily to reduce the complication and labor required for installin such systems in the aircraft, as well as to mini-1 mine the weight of the system when installed.

both of which are objects of prime importance,

especially in war time.

In such systems the dioxide supply comprises lower part of the fuselage and, ifa battery, they are manifolded togethersoas to act as a single flask, each having an operating head and one at least being of the type designed for actuation from a remote point to release the gas therefrom. Suchsource of dioxide is connected by iping to a selector valve at the pilots station and through the latter to-each of the several engine nacelles, or engine compartments therein, or to other fire hazards, so that the discharge of gas can be directed to any one of them, according to the pilots setting of such selector valve made at the time of the fire. Inasmuch as the dioxide pressure is normally above 800 lbs. per square inch and the piping must therefore be of the high-pressure kind, carefully set up from flask to selector, and thence by branches to the several engines, the installation of these systems requires much expert labor and a considerable total length of large-section, high pressure pipe with many joints and elbows; also it is often diflicult to find the necessary space at the pilots fore be'extended up to the pilots station with practically the same facility as electric wiring, being at the same time located out of the way and thus least exposed to injury. By such division of the system into related delivery and control sections or systems of the kind indicated,

the, new equipment involves least weight and,

one or a battery of flasks usually located in the more important, can be installed in the plane in much less time.

The principle of the present invention, a will presently appear, can be variouslyincorporated inaircraft and is shown in its form at present preferred, in the accompanying drawings wherein i Fig. 1 is a diagram layout of the system applie to a 4-engine aircraft;

Fig. 2, a structural portion thereof;

Fig. 3, a face view of the selector device;

Fig. 4, a section thereof; and v I Fig. 5, a section of one of the stopvalves.

While the proportions in Fig. 1 are exaggerated, it will be understood that the single flask I represents the whole source of dioxide, being located between decks or in the lower part of the station for the selector valve of the size required on account of the multitude of other connections also converging at that point.

According to this invention the gas delivery to the engine compartments is made through a system of discharge piping of the requisite diameter running in the shortest possible course fromthe source to each compartment to which gas is to be delivered as directly as the internal wing structure of the craft will permit, so that the total length (weight) of this high-pressure and largese'ction piping is a minimum, while the control of this system iseffected by an auxiliary connected system of flexible and smaller diameter line which alone are required to extend to the selector at the pilots station. Thi auxiliary system is constituted of relatively slender, flexible tubing 50 slender as to be regarded as hollow wire though perfectly capable of sustaining the pressures involved. Tubing of such dimension is of very low weight perunit length, usually of aluminum so that the total length used is not of such great. consequence and it can-therefore be trained or lacedthrough and between structural members and through spaces in the wings and body which would be inaccessible for installing ordinary jointed-piping. Itcan therefuselage or wherever most convenient. .The extinguishing gas is normally confined in the flask by its operating head 2 which can be understood to contain a sealing disc and apiercer therefor, not illustrated, but adapted to be remotely actuated by means of some appropriat operating connection, electric, hydraulic or mechanical, a pull-cable 3 being indicated in the present case, running up to the pilot's station.

When the flask head or piercer is actuated the released gas flows directly into the delivery pipingsystem 4 which, as stated, runs in the shortest convenient course from the flask directly through the Wing structures with branch connections 5 to each engine compartment. This piping is made up of large-section, high-pressure pipe, about one inch diameter, including the branches, thus to carry the full volume of the discharge when the gas is released into it.

Each branch 5 includes a stop valve 6 located at the. end of the branch nearest to the flask and therefore most remote from its engine compartment, .and each such valve (see Fig. 5) is normally closed by its spring 1, closure being in the direction of flow. The system is thus normally at atmospheric pressure and closed, so that in the event of a premature or accidental rupture of the sealing disc from any cause, the gas will be confined in the piping and no gas can'possibly reach anengine which, if that should happen,

would be stalled.

Any one of these valves can be selected for opening by the pilot, for which purpose the stem of each valve is provided with a piston 8 working in an appropriate cylinder incorporated in the valve structure, and each cylinder is connected we: the spring v 4,-and thepiston'l is made of adequate area i the valve disc with valve disc by a nne of the tubing or hollow wire a above referred to with the selector valve l0,which latter. is=located at'aipo'int on The drawings do notattempt to illustrate the devious courses'which these trol system resembles. electric wiring.-

, The control system is further connected to the L deliverysystern' by aline of tubing H which is tapped into the larger section piping ,4 at the nearest or most convenient point in the fuselage. The purpose o fwthis connection is, to admit gas ,pressureto the selector valve" at the appropriate time, for, transmission thereby, through one or toj open the respective the other .of the tubes 9,

stop. valve and according tofthe setting which has been given to'the valve by thej pilot, I

The selectoryalve itself can be'vari'ously; made; a

in'the present case itcomprises a flat valve disc I2 normally covering and closing the several, ports in'the valve body to which the several tubes 9 are connected. I uncover ,any one of [these ports thus to admit fluid pressure thereto from the tube H, [For this purpose-itis carried fast on a tubular arbor I I3 provided .wltha squared'stem H with which the handle is normally engaged. By the use of this handle the'valve disc canbe set to any desired station indicatedby its pointer IS in con-'- nection with a relatedindex on the face plate of the valve corresponding to theengine compartments or fire hazards.

, a when properly set by-the handle It the system is in readiness to deliver gas to the station selected but no gas is: delivered until the operating a head of the flask has been actuated; For this purpose the turn handle II is also con-- nected to the operating connection 3*abovereferred to; sojthat by merely pulling this handle off the stern ll the'sfealing disc"be'comes punc-- tured or opened, thus allowing the ga to expand Iintolthe twoi systems. Thereupon some of the released gas flowing through the tube I l" to the selector valve .continues on to that/particular stop valve, which was selectedby the pilot, and

acting .onthe piston .Bi-of'that valve opens it.-

The opening occurs against the combined pres- I, and the gas already in the delivery" piping resistance; ,Thereuponthe gas flows to the compartment oniira' The pull handle Iiis interlocked with the valve .casing, or its escutcheon plate, so that itcannot be pulled off-the. valve stem,'thus to release thebeen properly set to register one of the tubesli. e. one

'Ifhisis represented by a lug gas,- untilit has first of the fire hazards,

the craft most convenient to the'foperator and herein called the:

pilot's station;

flexible tubes must follow, in an actual plane, in order, to reach thepilot's station; in general the 'con-' It is adapted to' be rotated 'to for opening the st'op valve against possibility of, its entry to any enginecompartment. For additional security inthis respect the the valve disc against its seat. i a

the flask-actuating portingnoi the selector valve is sodesigned that any pressure therein acts in the direction to press When a cable is used for means it most conveniently extends from the handle through the tubular valve stem l3 and through'a tubular bracket l9 screwed into'the 'valve, and, over a guide-sheave carried on the 1 bracket. From thence it is trained over such other sheaves as may be necessary for connecting it' to theflask head, 'as will be understood, and it ..is customarily also enclosed between sheaves in a 1. In an airplane, the combination with a plurality of compartments on the-wings thereof to whichg'gas is to be delivered, of a gas delivery pipe .system extended through the wing structure having branches. respectively to such compartments and normally closed piston-operated stop valves pulled axially and a valve member operated by the rotation of such handle to be registered with anyone of such flexible tube lines, a flask of compressed gas remote from said station, a normally closed operating-head therefor connecting the flasl: to said deliverysystem', a gas connec tion from said deliveryv system to said selector valve; and anzoperating connection extending from said flask head to'saidhandle arrangedto be operated by the pullingof such handle, thereby substantially simultaneously opening said opieratinghead and one of said stop valves to admit gasintosaid delivery system and from the latter to the selectedcompartmentt 1 2. In an aircraft, the combination of the engine compartments and a gas delivery .pipe system extended through the wing structure with branches thereln,,respectively leading to such compartments'and piston-operated stop valves respectively located. in and normally closing each of such branchesysaid system comprising pipe of relatively large section adequate forrapid highpressure gas discharge 'therethrough, a control system including pressure transmitting tube lines ofrelatively smallsection-capable of easy flexure extending, from said stopvalves to the pilots I! cast on the handle and a corresponding" notched flange l8 applied to or, formed on the valve body, the lu'gand notches'being 'positionally correlatedto produce the ei'iect just stated, thus requiring a proper station selection to be made before thegas flow can be started; In thenormal or :non-use positionof the selector device, the

pointer registering at the normalsetting, the i2 overlies and closes all oithe flexible tube parts leading to the stop valves. and in this positionthe handle cannot be pulled on account of the interlock nor can a premature; gas release become. effective onfany of the stop valves;' in such" event and as already indicated;'t he gas is confined in'the pipe and tube systems, without station, amanual device includinga slector valve located=at suchstation connected with said tube lines ofsmaller section and adapted for manipulation to, select for action any one of such lines andthe piston of thestop;valve appurtenant thereto, a flask of compressed gas having a normally closed, operating headconnected to said delivery. pipc'system and also, connected to said selectoii valve, an operating handle for said device and an operatingconnection extending from said handle to saidiflask-operating head adapted for actuating the latterto release gas intoboth said systernsfor thereby actuating the selected stop -valve and admitting gas from said flask into the delivery system and-through said stop valve to a selectedcompartment. 1

CHARLES. H. LINDSAY.

conduit 2| so that it, will not he accidentally pulledi' v I @Iolaimav 

